Saturday, November 24, 2007

Minding Shop

With all of this hullabaloo about genome sequencing companies and what they might do with your genome, including possibly selling the "de-identified" data to pharma companies. A great business plan, but NOT personalized medicine. I actually received 3 emails pointing out the same idea. I do know a friend of mine who sold his plasmapheresis company to the British Government, not because of the need for products in the UK, but because Bayer was this company's biggest customer.

So the whole selling data/product to pharma is a plan which can make tons of money. Which could be the reason why the"genome" service is so cheap. Last time I checked, the best bet at the craps table is the pass line, provided you are on a come out roll. It's the proverbial hook.

With that being said, I want to come back to personalized medicine and a recent study published in the American Journal of Human Genetics in the December issue. We frequently counsel patients that BRCA positivity does not mean you will absolutely get breast cancer. In fact the likelihood is less than 90%

So what modifies this risk? Well, we know for certain of 1 gene called RAD51. This gene interacts with the BRCA genes and is required for a certain type of DNA repair, known as recombinational repair of double stranded DNA breaks. It is known to predispose patients to a blood cancer called AML.

To investigate the role of RAD51 common changes/SNPs in the modification of BRCA risk, these researchers investigated the results of 19 studies from very diverse populations. The results were decent. Not a home run per se, but they gave us some insight into the roll of SNPs in modifier genes. The study indicates that your risk for BRCA related breast cancer is increased with a SNP called 135 G to C.

The carriers of two copies of this change have a 3 fold increased risk if they are BRCA2 carriers. The increase 2 fold for BRCA1 carriers. Which brings me back to my interview with Bertalan Mesko at Scienceroll. The world of personalized genomics is here, we now have the tools to say why 100% similarity in expression. So what's next for this finding? Maybe it will find its way to an Illumina of Affy Chip? This certainly would be useful information prior to prophylactic mastectomy......

The Sherpa Says: Ahh, it feels good to tell you about data leading us up to the personalized medicine revolution. We must not take our eyes off the prize here. Party tricks with an algorithm not validated is NOT personalized medicine. But the results of this study once further replicated could be. Imagine reflex testing for RAD51 SNPs after you have the BRCA results. This could put the decision process into a less ambiguous path.

No comments: